Opening of Twin Tunnels Will Allow San Mateo County to Transform the Treacherous Stretch of Road Into a Recreation Area

PACIFICA—After nearly 80 years as one of California's most spectacular and hair-raising roadways, Devil's Slide—a 1.3-mile stretch in San Mateo County between Pacifica and Montara—is set to be turned into one of the most spectacular and hair-raising coastal trails in the state.

The roadway has been buffeted by decades of landslides and avalanches and sometimes has to be closed for repairs after such events. State engineers, aiming to provide a more reliable road along this part of the coast, are finishing work on twin...